drivers/usb/common/led.c

   1 // SPDX-License-Identifier: GPL-2.0
   2 /*
   3  * LED Triggers for USB Activity
   4  *
   5  * Copyright 2014 Michal Sojka <sojka@merica.cz>
   6  */
   7
   8 #include <linux/module.h>
   9 #include <linux/kernel.h>
  10 #include <linux/init.h>
  11 #include <linux/leds.h>
  12 #include <linux/usb.h>
  13
  14 #define BLINK_DELAY 30
  15
  16 static unsigned long usb_blink_delay = BLINK_DELAY;
  17
  18 DEFINE_LED_TRIGGER(ledtrig_usb_gadget);
  19 DEFINE_LED_TRIGGER(ledtrig_usb_host);
  20
  21 void usb_led_activity(enum usb_led_event ev)
  22 {
  23         struct led_trigger *trig = NULL;
  24
  25         switch (ev) {
  26         case USB_LED_EVENT_GADGET:
  27                 trig = ledtrig_usb_gadget;
  28                 break;
  29         case USB_LED_EVENT_HOST:
  30                 trig = ledtrig_usb_host;
  31                 break;
  32         }
  33         /* led_trigger_blink_oneshot() handles trig == NULL gracefully */
  34         led_trigger_blink_oneshot(trig, &usb_blink_delay, &usb_blink_delay, 0);
  35 }
  36 EXPORT_SYMBOL_GPL(usb_led_activity);
  37
  38
  39 static int __init ledtrig_usb_init(void)
  40 {
  41         led_trigger_register_simple("usb-gadget", &ledtrig_usb_gadget);
  42         led_trigger_register_simple("usb-host", &ledtrig_usb_host);
  43         return 0;
  44 }
  45
  46 static void __exit ledtrig_usb_exit(void)
  47 {
  48         led_trigger_unregister_simple(ledtrig_usb_gadget);
  49         led_trigger_unregister_simple(ledtrig_usb_host);
  50 }
  51
  52 module_init(ledtrig_usb_init);
  53 module_exit(ledtrig_usb_exit);